Modulating control valve for hydraulically operated winch

ABSTRACT

A hydraulically operated winch of the type adapted for logging or towing operations and having a rotatable winch drum about which a cable or line is entrained, a normally disengaged clutch being hydraulically operable to provide a coupling between a power input member and a winch drum drive shaft, a normally engaged friction brake normally securing the winch drum drive shaft against rotation while being hydraulically disengagable and a normally engaged clutch providing a selective coupling between the winch drum drive shaft and the winch drum. A modulating control valve for the winch includes a valve body having an inlet chamber in communication with a source of fluid under pressure, a single regulating spool in the valve being operable to selectively communicate fluid under pressure from the inlet chamber with respective actuating chambers for the brake and the two clutches, the valve also including a modulating valve responsive to the positioning of the regulating spool for modulating fluid pressure in the inlet chamber.

United States Patent Schmitt et al.

[451 Oct. 15, 1974 Primary Examiner-Richard A. Scha'cher AssistantExaminer-Jeffrey V. Nase Attorney, Agent, or Firm-Phillips, Moore,

ABSTRACT A hydraulically operated winch of the type adapted for loggingor towing operations and having a rotatable winch drum about which acable or line is entrained, a normally disengaged clutch beinghydraulically operable to provide a coupling between a power inputmember and a winch drum drive shaft, a normally engaged friction brakenormally securing the winch drum drive shaft against rotation whilebeing hydraulically disengagable and a normally engaged clutch providinga selective coupling between the winch drum drive shaft and the winchdrum. A modulating control valve for the winch includes a valve bodyhaving an inlet chamber in communication with a source of fluid underpressure, a single regulating spool in the valve being operable toselectively communicate fluid under pressure from the inlet chamber withrespective actuating chambers for the brake and the two clutches, thevalve also including a modulating valve responsive to the positioning ofthe regulating spool for modulating fluid pressure in the inlet cham- 6Claims, 7 Drawing lFigures [75] Inventors: 2355 'gf g xg z ofWeissenberger, Lempio & Strabala ill. [73] Assignee: Caterpillar TractorCo., Peona, ill. [5 71 [22] Filed: Feb. 21, 1973 [21] Appl. No.: 334,353

[52] 11.5. C1 254/187 R, 137/625.69, 192/18 A, 254/166 [51] Int. Cl B66d1/44 [58] Field of Search 254/187 R, 166, 150 FH; 137/596, 625.42,625.48, 625.69; 91/413; 192/18 A [56] References Cited UNITED STATESPATENTS 2,881,882 4/1959 Gentile 254/187 R 2,986,884 6/1961 254/150 FH3,027,141 3/1962 254/166 3,027,722 4/1962 137/625.42

3,070,324 12/1962 Bryman 254/166 3,295,420 1/1967 Gleason 91/4133,325,149 6/1967 Woodward 254/187 R 3,529,702 9/1970 Eckstein 254/187 R3,756,564 9/1973 Murray et a1 254/150 FH 72- g 92- t s [I m I I I .101 T7&- 73 97 PATENTEB BUT I 5 I974 SHEET t 0F 4 V V mm R. mw

MODULATING CONTROL VALVE FOR HYDRAULICALLY OPERATED WINCH BACKGROUND OFTHE INVENTION The present invention relates to a hydraulically operatedwinch and a modulating control valve for operating the winch.

The winch is preferably of a type adapted for mounting upon a vehicleused in towing or logging applications. The winch is furthercontemplated as having a normally disengaged clutch which ishydraulically operable for driving a winch drum in rotation, a normallyengaged brake being operable in opposition with the normally disengagedclutch to hold the winch drum against rotation for supporting a load oralone to selectively permit rotation of the winch drum, for example inlowering a load, an additional clutch being normally engaged to providea coupling between the winch drum and a drive shaft while beinghydraulically disengagable to permit free wheeling of the winch drum.

A winch of this type is disclosed in greater detail by a co-pending U.S.Pat application Ser. No. 334,354 filed on Feb. 21, I973 by Lyle F. Yateset al.

As noted in the co-pending Patent application, it is desirable toprovide for operation of such a winch system in a plurality of modes bya single control element. For example, it is desirable to synchronouslyoperate the brake and the normally disengaged clutch in order to reel ina load, to hold the load by means of the brake and to selectivelyrelease the load by partially or completely disengaging the brake. In afurther mode of operation, it is desirable to selectively disengage thenormally engaged clutch to permit free wheeling of the winch drum. Thismode of operation facilitates manual unwinding of cable from the winchdrum for example by eliminating drag caused by internal components ofthe winch assembly.

SUMMARY OF THE INVENTION Accordingly, it is an object of the presentinvention to provide a winch of the type disclosed above together with amodulating control valve for operating the winch assembly.

It is a further object of the invention to provide a modulating controlvalve which is operable for actuating a normally disengaged clutch, anormally engaged brake and a normally engaged clutch respectivelyarranged within a power train for a winch drum of the winch assembly.

It is a further object of the invention to provide such a modulatingcontrol valve having a single regulating spool for selectively actuatingthe two clutches and the brake of such a winch assembly.

It is a still further object of the invention to provide such amodulating control valve having therein modulating means which are alsoresponsive to the regulating spool.

Additional objects and advantages of the present invention are madeapparent in the following description having reference to theaccompanying drawings.

BRIEF SUMMARY OF THE DRAWINGS FIG. I is a side elevation view ofa logskidder including a towing or logging winch constructed according to thepresent invention.

FIG. 2 is a schematic representation of the winch drum and drive trainincluded within the winch assembly of FIG. 1.

FIG. 3 is a side view with parts in section of a hydraulic controlvalve, additional components of a hydraulic control circuit for thewinch assembly of FIGS. 1 and 2 being illustrated schematically.

FIGS. 4 and 5 are views similar to FIG. 3 with the control valve beingillustrated in different operating positions.

FIG. 6 is a graphical representation of pressure traces developed by thecontrol valves of FIGS. 3-5 in accordance with displacement of aregulating spool from a centered position within the valve assembly.

FIG. 7 is a simple representation of a shift pattern for a singlecontrol member controlling the regulating spool within the control valveassembly of FIGS. 3-5

DESCRIPTION OF A PREFERRED EMBODIMENT A winch constructed according tothe present invention is particularly adapted for use as a towing orlogging winch in a log skidder vehicle of the type illustrated at 11 inFIG. 1. The vehicle and winch assembly are also described in greaterdetail within the copending Patent application referred to above.

The vehicle 11 of FIG. 1 includes a prime mover or engine as illustratedin phantom at 12. To adapt the vehicle for logging operations, it mayinclude a bulldozer blade mounted upon one end of the vehicle formovement between a raised position illustrated in solid lines at 13 anda lowered position illustrated in phantom at 13'. To adapt the vehiclefor towing operations, it includes an arch arranged upon the other endof the vehicle as illustrated at 14 and a winch assembly as indicated at16.

Referring particularly to FIG. 2, a power train for the winch assemblyincludes a power input shaft 21 which may comprise a standard powertake-off from the prime mover 12 of the vehicle in FIG. I for example.The input shaft 21 is coupled by means of meshing transfer gears 22 and23 with an input shaft 24 for a normally disengaged friction clutch 26.An output shaft 27 for the clutch 26 is coupled with a clutch outputgear 28 which is secured for rotation with a transfer gear 29. Theclutch output gear 28 meshes with a brake gear 31 while a normallyengaged. friction brake 32 is operable to secure the brake gear 31against rotation.

The components described above in engagement with the input shaft 21comprise an intermediate portion of the drive train. The normallydisengaged clutch 26 permits driving operation of the gear componentswithin he intermediate drive train by the input shaft 21. The normallyengagee brake 32 in one mode of operation, tends to be disengaged as theclutch 26 is engaged or conversely, tends to be engaged as the clutch 26is disengaged. Thus, the brake 32 serves to prevent rotation of theintermediate drive train or at least those components on the output sideof the clutch 26 when the clutch 26 is disengaged. In this connection,the hydraulic control system described below is adapted to selectivelyoperate the brake 32 and clutch'26 in opposition with each other or tooperate the brake 32 alone, the control system having a hydrauliccontrol valve with modulating means particularly adapted for operationof the brake 32 and clutch 26.

An output portion of the winch drive train includes a transfer gear 33arranged in meshing engagement with the gear 29. The gear 33 is mountedupon an input shaft 34 for a bevel gear assembly 36 having bevel gears37 and 38. A winch drum shaft 39 provides an output for the bevel gearassembly 36 with a winch drum 41 being arranged for rotation upon theshaft 39 by means of bearings 42 and 43.

A jaw-type clutch 44 is normally engaged to provide a coupling betweenthe winch drum shaft 39 and the drum 41 while being selectivelydisengageable to permit free wheeling of the drum 41. Referringmomentarily to FIG. 1, it may be seen that a line or cable 46 isentrained about the drum 41 for operation in conjunction with the arch14.

Referring now to FIGS. 3-5, a hydraulic control circuit for operatingthe winch assembly of FIGS. 1 and 2 is constructed according to thepresent invention to include a a single, relatively simple control valve51 operable by a single control element as discussed in greater detailbelow to operate the winch assembly 16 in three distinct modes ofoperation. The control valve 51 includes a regulating spool 52 slidablyarranged in a bore 53. The regulating spool 52 controls fluidcommunication between an inlet chamber 54 and actuating chambers 26, 32and 44' for the clutches and brake referenced by corresponding numeralsin FIG. 2. Fluid pressure within the inlet chamber 54 is modulated by amodulating valve assembly 56 which is also responsive to positioning ofthe regulating spool 52.

The three operating conditions referred to above include a hold positionwith the regulating spool 52 being in its centered position asillustrated in FIG. 3. In this condition, the two clutches 26, 44 andthe brake 32 are in their normal conditions; in other words, the clutch26 is disengaged, the clutch 44 is engaged, and the brake 32 is engaged.In a second operating condi tion, the regulating spool 52 is moveable ina leftwardly direction as viewed in FIG. 3 toward a position illustratedin FIG. wherein the brake 32 is gradually released and the clutch 26 isengaged for reeling in the line or cable illustrated at 46 in FIG. ll.

' The regulating spool 52 is also moveable in a rightward directiontoward the position illustrated in FIG. 4. However, before the spool ismoved fully into the position of FIG. 4, the brake 32 is again graduallyreleased to permit lowering or releasing of a load supported by thecable 46 of FIG. 1. In this mode of operation, it is noted that theclutch 26 is not simultaneously engaged. The regulating spool 52 isfurther moveable in a rightward direction to a position as illustratedin FIG. 4 where the brake 32 remains disengaged and the clutch 44 isalso completely disengaged to permit free wheeling operation of thewinch drum 41. This operating position enables an operator to manuallyunreel cable from the drum 41 free from drag which would normally arisefrom the numerous internal winch components.

Particular features of the control circuit are described below havingparticular reference to FIG. 3 with the alternate positions of theregulating spool 52 being subsequently described with reference to FIGS.4 and 5.

Referring now to FIG. 3, the control valve 51 includes a valve body 51'which forms the bore 53 for receiving the regulating spool 52. Therightward end of the housing 51 is closed by an end cover indicated at57. The regulating spool 52 is urged into its centered position by aspring indicated at 58. A sleeve 59 limits travel of the regulatingspool 52 in either direction from its centered position illustrated inFIG. 3. For example, when the spool 52 moves in a rightward direction,the sleeve 59 permits such travel until it engages a washer indicated at61. The regulating spool 52 may also move in a leftward direction fromits centered position until the washer 61 is shifted leftwardly intocontact with the sleeve 59.

A separate portion of the housing 51' forms concentric bores 62 and 63of different diameters which respectively contain a load position 64 anda modulating relief valve spool 66 which comprise the modulating valveassembly 56. A pair of springs 67 and 68 are arranged for interactionbetween the load piston 64 and the relief valve spool 66. Anintermediate stepped bore 69 provides clearance for the outer spring 68and is also in communication with a fluid drain indicated at 71. It maybe noted in the following description that the numeral 71 is employed todesignate a common drain for various portions of the control valvecircuit. The leftward end of the bore 62 is also closed by an end cover72 which thus acts as a stop for leftward movement of the load piston64.

When the regulating spool 52 is in its centered position as illustratedin FIG. 3, the hydraulic circuit is supplied with hydraulic fluid underpressure from a pump or source 73 which draws fluid from the drain orsump 71 through a filter 74. Fluid from the pump 73 is supplied to theinlet chamber 54 through a conduit 76. With the regulating spool beingin its normally centered position of FIG. 3, the relief valve spool 66produces a pressure of approximately 50 psi within the inlet chamber 54as is also graphically represented in FIG. 6. A check valve 77,producing a pressure drop of approximately 20 psi communicates fluidfrom the inlet chamber 54 into an annular recess 78 formed about thebore 53. As the spool 52 is moved in either direction from its centeredposition of FIG. 3, a plurality of metering slots 79 formed upon thepool communicate fluid from the annular recess 78 with a branched port81 which is in communication with the brake actuating chamber 32'.

Fluid under pressure from the inlet chamber 54 is also communicatedthrough an orifice 82 to open a low pressure check valve 83 and enter achamber 84 to act against the modulating relief valve spool 66.Accordingly, the modulating relief spool 66 tends to be shifted towardthe left against the springs 67 and 68 in order to provide meteredcommunication between the inlet chamber 54 and a lubrication passage 86.A relief valve 87 is adjusted to limit pressure within the lubricationpassage 86 to approximately 35 psi with excess fluid pressure beingcommunicated to the fluid drain 71.

A small diameter damping orifice 88 permits retarded movement of thespool 66 in a rightward direc tion to close off the lubrication passage86 in the event of substantial force produced upon the spool 66 by theload piston 64 or in the event of a rapid pressure drop within the inletchamber 54.

With the regulating spool 52 being in its centered position asillustrated in FIG. 3, additional metering slots 90 formed thereon placethe brake port in communication with the fluid drain 71 by means of adrain port 89. Another port 91 which is in communication with the clutchactuating chamber 26' is also in communication with the drain port 89when the regulating spool 52 is in its centered position.

The modulating load piston 64 is urged leftwardly by the springs 67 and68 into a load piston chamber indicated at 92. The load piston chamberis in communication with the inlet chamber 54 by means of a restrictiveorifice indicated at 93. The restrictive orifice 93 is selectively sizedto provide a modulating function as described in greater detail below.The load piston cham ber is also in communication with a drain port 94which crosses the regulating spool bore 53 for communication with thefluid drain 71. The regulating spool 52 in cludes an annular groove 96which provides fluid continuity for the drain port or passage 94 whenthe regulating spool 52 is in its centered position as illustrated inFIG. 3. However, as the regulating spool is shifted in either direction,fluid communication along the drain passage 94 is interrupted so thatfluid pressure crossing the orifice 93 tends to produce increasingpressure within the load piston chamber 92. Accordingly, it may be seenthat the rate of pressure rise within the load piston chamber 92 andaccordingly the rate of modulation accomplished by the load piston 64and the relief valve spool 66 in combination with the springs 67, 60 isdependent upon the size of the restrictive orifice 93. It is furtherobvious from FIGS. 3-5, for example, that the rate of modulation is alsodependent upon the relative areas of the load piston 64 and the reliefvalve spool 66 which are responsive to fluid pressure in the chambers 92and 84 respectively.

Fluid from the conduit 76 is also delivered across a low pressure checkvalve 97 to a conduit 98 which is in communication with a fluid pressureaccumulator indicated at 99. Additional slots 101 formed by theregulating spool 52 serve to communicate a port 102, in communicationwith the conduit 98, with the branched brake port 81. This mode ofcommunication is provided when the regulating spool is shifted fully tothe right to the position shown in FIG. 4 to provide an emergency meansfor releasing the brake 32 in the event of low pressure or completepressure loss in the control circuit.

It is believed that the manner of operation for the present controlcircuit is obvious from the above description. However, a briefdescription of the method of operation for the control circuit is setforth below. As the regulating spool is moved in a leftward directiontoward the position of FIG. 5, the groove 96 passes out of register withthe drain passage 94 so that fluid pressure is developed within the loadpiston chamber 92 depending upon the size of the orifice 93. The widthof the groove 96 is approximately 0.1 inches so that the basic pressureof 50 psi as noted above is maintained in the inlet chamber 54 untilmovement of the regulating spool 52 exceeds that distance in eitherdirection. Pressure in the chamber 54 is then increased toward a maximumof about 350 psi for example. With additional movement of the regulatingspool in a leftward direction, the brake port 81 is gradually placed incommunication with the annular recess 78 by the metering slot to fillthe brake actuating chamber 32' and gradually release the brake 32.Simultaneously, the port 91 for the clutch actuating chamber 26' issimultaneously closed for communication with the fluid drain 71 andplaced in communication with the inlet chamber 54 across an annulargroove 103 in the spool 52. Thus, with the brake 32 being released andthe clutch 26 being engaged, the winch drum 41 is rotated to reel in theline or cable 46 as seen,in FIG. 1.

As the regulating spool 52 is shifted rightwardly from its centeredposition, the metering slot 79 again provides gradual communicationbetween fluid pressure in the annular recess 76 and the branched conduit81. However, the clutch actuating chamber 26' is maintained incommunication with the fluid drain port 89. Thus, the brake 32 isgradually released at a selectively controlled rate to permit thelowering or releasing of a load supported by the cable 46.

With the spool 52 being moved further to the right into the positionillustrated by FIG. 4, the groove 103 communicates the inlet chamber 54with the clutch actuating chamber 44'. Accordingly, with the regulatingspool being shifted completely to the right as viewed in FIG. 4, theclutch 44 is completely disengaged to permit free wheeling rotation ofthe winch drum 41.

It may be noted that with movement of the regulating spool 52 in eitherdirection from its centered position illustrated in FIG. 3, fluidpressure within the inlet chamber 54 is modulated as required forproviding a pressure supply to the actuating chambers for the respectiveclutches and brake.

In addition to assisting in this modulation function, the modulatingvalve spool 66 also serves to provide limited pressurization within thelubrication passage 66. This function is of relative importance withinsuch a winch assembly to provide for example for cooling of therespective clutches and brake with heat being generated by thesubstantial forces arising in the winch system. thus being removed bythe cooling fluid from the lubricating passage 86.

The shift pattern for a control element as viewed in FIG. 7 may be seenas corresponding with the axial position of the regulating spool 52 inFIGS. 3-5. Means are provided to lock the control element 104 in theposition illustrated in FIG. 7. Thus, the operator may leave the vehiclewith the clutch 44 being disengaged in order to unreel cable from thedrum 41 in the manner referred to above.

What is claimed is:

1. A hydraulically operated winch comprising a rotatable winch drum,

a power train having a normally disengaged clutch being hydraulicallyengageable for operatively coupling a power input means with a winchdrum drive shaft, a normally engaged brake effectively securing thewinch drum drive shaft against rotation while being hydraulicallyreleasable to permit rotation of the winch drum drive shaft and a clutchnormally coupling the winch drum drive shaft with the winch drum whilebeing hydraulically disengageable to permit free-wheeling of the winchdrum,

a source of fluid under pressure, and

a modulating control valve having a valve body defining an inlet chamberin communication with the fluid source and a bore, the bore being incommunication with the inlet chamber, an actuating chamber for releasingthe normally engaged brake, an actuating chamber for engaging thenormally disengaged clutch and an actuating chamber for disengaging thenormally engaged clutch, a single regulating spool being slidable in abore with resilient means urging the regulating spool into a centeredposition in the bore wherein the spool communicates all of the clutchand brake chambers with fluid drain means, the single regulating spoolbeing movable in a first direction of travel from its centered positionfor variably communicating both of the actuating chambers for the brakeand the normally disengaged clutch with the inlet chamber, theregulating spool being movable in a second direction of travel from itscentered position for variably communicating the brake actuating chamberwith the inlet chamber, the regulating spool being further movable inits second direction of travel for communicating the actuating chamberof the normally engaged clutch with the inlet chamber and means forselectively modulating fluid pressure within the inlet chamber.

2. The hydraulically operated winch of claim 1 further comprising anaccumulator means in effective communication with the inlet chamber bymeans of a check valve and in communication with the regulating spoolbore, the regulating spool being effective to communicate theaccumulator means with the brake actuating chamber as the regulatingspool is moved from its centered position.

3. The hydraulically operated winch of claim 2 wherein the regulatingspool comprises metering means for variably communicating the inletchamber with the brake actuating chamber as the regulating spool ismoved from its centered position.

4. The hydraulically operated winch of claim 3 wherein the regulatingspool comprises additional metering means for variably communicating thebrake actuating chamber with the fluid drain means as the regulatingspool is returned toward its centered position from its first directionof travel.

5. The hydraulically operated winch of claim 1 wherein the regulatingspool comprises metering means for variably communicating the inletchamber with the brake actuating chamber as the regulating spool ismoved from its centered position.

6. The hydraulically operated winch of claim 5 wherein the regulatingspool comprises additional metering means for variably communicating thebrake actuating chamber with the fluid drain means as the regulatingspool is returned towards its centered position.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,8r1,608 DATED October 15, 197 4 INVENTOR(S) James L. Schmitt, et a1 It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

On the Title Page, Item [7'3], change the spelling of the assignee'scorporate address from "Peona, Ill. to

-- Peoria, Ill.

Signed and Sealed this A ties t:

RUTH C. MASON Arresting Officer C. MARSHALL DANN ('mnmr'ssimrvruflarenlx and Trademarks

1. A hydraulically operated winch comprising a rotatable winch drum, apower train having a normally disengaged clutch being hydraulicallyengageable for operatively coupling a power input means with a winchdrum drive shaft, a normally engaged brake effectively securing thewinch drum drive shaft against rotation while being hydraulicallyreleasable to permit rotation of the winch drum drive shaft and a clutchnormally coupling the winch drum drive shaft with the winch drum whilebeing hydraulically disengageable to permit free-wheeling of the winchdrum, a source of fluid under pressure, and a modulating control valvehaving a valve body defining an inlet chamber in communication with thefluid source and a bore, the bore being in communication with the inletchamber, an actuating chamber for releasing the normally engaged brake,an actuating chamber for engaging the normally disengaged clutch and anactuating chamber for disengaging the normally engaged clutch, a singleregulating spool being slidable in a bore with resilient means urgingthe regulating spool into a centered position in the bore wherein thespool communicates all of the clutch and brake chambers with fluid drainmeans, the single regulating spool being movable in a first direction oftravel from its centered position for variably communicating both of theactuating chambers for the brake and the normally disengaged clutch withthe inlet chamber, the regulating spool being movable in a seconddirection of travel from its centered position for variablycommunicating the brake actuating chamber with the inlet chamber, theregulating spool being further movable in its second direction of travelfor communicating the actuating chamber of the normally engaged clutchwith the inlet chamber and means for selectively modulating fluidpressure within the inlet chamber.
 2. The hydraulically operated winchof claim 1 further comprising an accumulator means in effectivecommunication with the inlet chamber by means of a check valve and incommunication with the regulating spool bore, the regulating spool beingeffective to communicate the accumulator means with the brake actuatingchamber as the regulating spool is moved from its centered position. 3.The hydraulically operated winch of claim 2 wherein the regulating spoolcomprises metering means for variably communicating the inlet chamberwith the brake actuating chamber as the regulating spool is moved fromits centered position.
 4. The hydraulically operated winch of claim 3wherein the regulating spool comprises additional metering means forvariably communicating the brake actuating chamber with the fluid drainmeans as the regulating spool is returned toward its centered positionfrom its first direction of travel.
 5. The hydraulically operated winchof claim 1 wherein the regulating spool comprises metering means forvariably communicating the inlet chamber with the brake actuatingchamber as the regulating spool is moved from its centered position. 6.The hydraulically operated winch of claim 5 wherein the regulating spoolcomprises additiOnal metering means for variably communicating the brakeactuating chamber with the fluid drain means as the regulating spool isreturned towards its centered position.